I received a Frenzied Goblin as the FNM Promo tonight and it is not part of the Promo set in MTG Studio. It has differing card art from M15/Ravnica versions of Frenzied Goblin, has the FNM Promo set symbol, and is a foil version of the card.

I'm not sure what the typical process is to get promo/one-off cards added into the system. Hope this helps however.